Biomedical subjects
Publications and source records attributed to A Brun.
Subcutaneous inoculation of minced brain tissue from a case of progressive multifocal leukoencephalopathy into newborn Syrian hamsters produced transplantable angiosarcomas in 2 of 11 animals. Immunostaining revealed the presence of SV40 in the progressive multifocal leukoencephalopathy (PML) tissue, indicating this virus as the tumor-inducing agent.
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The kinetics and the titre of the serum neutralising antibodies have been studied for 55 months, in eight cows already vaccinated against rabies with a commercial vaccine. The titres remained stable during this period and increased after the booster injection 16 months after the primary immunization. The protection obtained with this vaccine was tested. These cattle and five controls were inoculated in each masseter muscle in the 55th month with a street rabies virus suspension (5 x 10(5) MICLD50). None or very low serum neutralising antibody titres were found among the controls. However, the inoculation of street rabies virus elicited an irregular immune response among the vaccinated cows. All the controls died whereas all the cows which had received one booster injection survived.
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Vaccination against Swine Fever using the CL Chinese strain can be done in 7-day-old piglets if they are born of non-immune sows. The simultaneous weaning and vaccination emphasises the safety of this strain. The excellent immunity observed confirms the immunocompetence of 7-day-old piglets. In piglets born of immune sows and also weaned at 7 days, passive protection can extend beyond the age of 2 months if the sow is vaccinated several months prior to gestation. The immune level of the piglets would seem to depend on the interval between vaccination of the sow and farrowing and can be attributed to the quality of the antibodies transmitted by the colostrum. Piglets born of sows vaccinated 10 months prior to farrowing can be vaccinated as early as 5 weeks; the protection percentage observed at the age of about 6 months is over 80%. A booster injection at this age then confers immunity to future breeders throughout their economic life, i.e. 4 years in the reported experiment.
Four cases of "delayed" sudden infant death are described in infants, who were found lifeless and were resuscitated, but did not regain consciousness. Circulatory failure occurred 20-48 hours later. In these cases, one could expect an accentuation of such lesions which might have caused the collapse. Among the cases there were bronchopneumonia, areas of coagulative myocardial necrosis without cellular reaction, and gliosis of the cerebral white matter and the brain stem of focal as well as diffuse type. The CNS changes were of hypoxic type and might have been caused at delivery or shortly after delivery. They seem too insignificant to have caused the collapse, but could have been an auxiliary factor. It cannot be determined whether the bronchopneumonia caused the collapse or if it developed as a consequence of the unconsciousness. Interestingly, no other pathological changes of significance were found.
The authors report a case of methemoglobinemia following a suicidal attempts with a popper containing isobutyl nitrite. The toxic effects of this substances, either by ingestion or inhalation, are described as well as risks of use in "everyday life". Regulations, still incomplete has been suggested in USA. In France, preventive measures should be taken.
The rotavirus is considered as being one of the major causes of acute gastroenteritis; it occurs in cattle farms where, either by itself or in association with other pathogenic agents, it is responsible for a high percentage of neonatal morbidity and mortality. Over two consecutive years, field trials were done using inactivated rotavirus vaccine in oily excipient inoculated to pregnant cows. Results obtained prove a significant increase in the rate of colostral antibodies and a very real prolongation of the excretion of these antibodies into the milk up to and over 28 days post-calving. From the clinical point of view, outbreaks of diarrhoea in calves born of vaccinated cows were less common and less serious, but more importantly, the rotavirus was found to be playing a far less significant role. It was thus demonstrated that the presence of a great quantity of specific antibodies in the intestine plays a protective role. This mechanism was the origin of the concept of lactogenic immunity and is particularly well demonstrated by the study of viral excretion at the virulent challenge of calves having followed differing lactation programmes.
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Transplantation of human brain tumours into the brain of normal laboratory animals is still considered to be unsatisfactory by many researchers, despite the fact that the brain is considered an immunologically privileged site. We present in this paper a model of xenotransplantation fo human astrocytomas grade III-IV into the brain of normal, adult Sprague-Dawley rats with good take rates, i.e. takes in two thirds of the animals, half of these with large, infiltrating tumours. The transplants are placed using a microsurgical technique in the vessel-rich choroidal fissure in the host brain from where rapid vascularization occurs. The technique has previously been used for CNS-regeneration studies. This model should provide an excellent opportunity to study human malignant astrocytomas in a milieu as natural as possible.
The challenge we carried out, which regularly brought about the death of the control animals, led us to study the different factors influencing the pathogenicity of the rabies virus. So, the method of preparation is important. The strain NYC, prepared from the salivary glands is extremely pathogenic for dogs; however, when it is prepared from mouse brains after nine passages have been made, it proves to be already partially modified. One then notices a death-rate which is less severe, even when larger quantities of virus are employed, and also the presence of some aberrant phenomena. (The survival of some of the infected animals and the nature of their inapparent forms of infection were confirmed by serology.) The significance of the route of inoculation in the different species of animals was studied. The injection in the crotaphytes was reserved for dogs, the cervical muscles for cats and the masseters for sheep. Paradoxically, cats prove to be most resistant to the challenge under our conditions. Finally the numerical data, allowing us to compare the different strains, modified, fixed or wild, was established. The data was based on the incubation period and on the differences between the titres obtained via intramuscular routes and intracerebral routes in the mice.
Further to guidelines advised by the World Health Organization, an inactivated Rabies vaccine was prepared from virus propagated on cell culture. This vaccine is presented either in the freeze-dried form or in the liquid form together with an immunity adjuvant. The specific and nonspecific immunity of the vaccine is excellent. The potency, tested in laboratory animals and in species for which the vaccine is intended, satisfies recommendations published by the W.H.O. The immunity persistence, evaluated by the titration of serum antibodies and by challenge with a pathogenic virus, proves to be excellent 3 years following primovaccination. Finally, the stability of this vaccine is an interesting factor for its application, especially in the form of a combined vaccine.
The photohemolysis of normal erythrocytes incubated with protoporphyrin is reduced in the presence of albumin. When globin is added to normal erythrocytes loaded with protoporphyrin, protoporphyrin is bound to globin. During irradiation protoporphyrin moves from globin to the erythrocyte membrane and photohemolysis is initiated. Erythrocytes in patients with erythropoietic protoporphyria contain large amounts of protoporphyrin bound to hemoglobin. Upon irradiation of these cells in the absence of albumin, 40% of protoporphyrin and 80% of hemoglobin is released after 240 kJ/m2. The released protoporphyrin is hemoglobin bound. In contrast, when albumin is present only 8% of hemoglobin is released whereas protoporphyrin is released to 76%. The released protoporphyrin is albumin bound. A hypothesis for the release of erythrocyte protoporphyrin in erythropoietic protoporphyria without simultaneous hemolysis is proposed. Upon irradiation protoporphyrin photodamages its binding sites on hemoglobin, moves through the plasma membrane, and is bound to albumin in plasma.